It is known that the reaction of carbon with fluorine or fluorine/chlorine at sufficiently high temperature to induce reaction leads to the formation of stoichiometric and non-stoichiometric carbon fluoride products, CF.sub.x or carbon fluoride chloride products, (C.sub.y F.sub.x Cl.sub.z).sub.n. The nature of the product depends not only on the temperature but on the carbon used in the reaction. These materials are currently in demand because they exhibit unique properties due to the varying degree of covalently bonded fluorine (the x value). Included among typical uses are: solid lubricants or lubrication additives, e.g., U.S. Pat. Nos. 3,717,576 and 3,988,137; water repellants, e.g., U.S. Pat. No. 3,856,686 and as a cathode active component in a non-aqueous primary cell, e.g., U.S. Pat. No. 3,536,532. As a measure of good performance, the materials must exhibit high temperature and pressure stability. This is usually achievable only if the fluorine to carbon ratio is 1 or greater. This combination of properties is acknowledged in the art as being usually found in graphite based materials, as opposed to carbon black based materials.
The synthesis of graphite based CF.sub.x is accomplished at around 620.degree.-635.degree. C. Typical of the synthetic procedures is that disclosed in U.S. Pat. No. 3,674,432 to Margrave, et al. This patent details the conditions required to form CF.sub.x from a graphite feedstock. As described in this patent, a very narrow temperature range of 624.degree.-630.degree. C. is required to prepare CF.sub.x of the desired fluorine to carbon ratio (x.gtoreq.1). Using temperatures substantially below that described in the Margrave work results in the formation of incompletely fluorinated products (35-53% fluorine content; x=0.34-0.71) and does not produce a product with the desirable characteristic alluded to above reference being made to Japanese Kokai No. 76-30,597 and to Chem. Abstr. No. 85:48901b.
The hazards of fluorinating graphite at temperatures close to the decomposition temperature of the product CF.sub.x are recognized. In column 8, lines 27-30 of U.S. Pat. No. 3,674,432, for example, it is noted that a too rapid increase in fluorine pressure or an increase in the fluorine pressure to a point above the reaction pressure may cause an explosion. Since that time, more comprehensive studies of the thermal decomposition of graphite fluoride under various conditions have been made with similar conclusions. Depending upon the atmosphere present during the thermal degradation experiments, a decomposition temperature as low as 562.degree. C. has been observed in an oxygen atmosphere. These results imply that the more oxidizing the atmosphere, the greater the probability of decomposition occurring at a lower temperature. In view of the strong oxidizing power of fluorine, it becomes apparent that thermal decomposition of CF.sub.x could occur during its manufacture if the partial pressure (% volume) of fluorine reached a critical value at these elevated temperatures. Consequently, the propagation of gaseous fluorocarbon by-products would be enhanced, the formation of which could result in a violent explosion.
It is thus seen that a need exists to define a safe process for the production of CF.sub.x from a graphite feedstock. A method of producing a graphite based CF.sub.x, for example, at a temperature substantially lower than the decomposition temperature would be desirable. A need also exists to define a safe process for the production of carbon fluoride chloride from a graphite feedstock.